In the field of semiconductor devices such as an Integrated Circuit (IC), Large Scale Integration (LSI), and Magnetoresistive Random Access Memory (MRAM), attempts have been made to reduce the wiring size, the wiring resistance, and the dielectric constant of an interlayer insulating film in order to improve the operating speed and the degree of integration. As for the wiring metals, copper or copper alloy has been employed due to recent problems such as wire delay.
Such copper or copper-alloy wiring is formed by, for example, the damascene method. In the damascene method, generally, grooves (concave portions) serving as the wiring portion are formed on an interlayer insulating film, and copper or copper alloy is deposited thereon, or, after the formation of such grooves, a thin barrier film of tantalum or tantalum nitride is formed on the surface of the interlayer insulating film including these grooves, followed by deposition of copper or copper alloy thereon. At this time, excessive copper or copper alloy is deposited. Thus, planarization is carried out by removing the excessive copper or copper alloy through polishing by a Chemical Mechanical Polishing (CMP) method until the interlayer insulating film or the barrier film is exposed. By so doing, wiring composed of copper or copper alloy embedded in grooves is formed in semiconductor devices.
As a polishing technique by using the CMP method, for example, there is a technique for polishing a substrate having a silicon-containing dielectric layer which uses a CMP system comprising an abrasive, a polishing additive having a functional group of pKa 3 to 9, and a liquid carrier (for example, refer to Published Japanese translation No. 2006-520530 of PCT International Publication). According to the technique described in the above Patent Document, the CMP system can exhibit desirable planarization efficiency, selectivity, uniformity, and removal rate, while minimizing defects.
Moreover, as another polishing technique by using the CMP method, there is a polishing method which uses an abrasive containing a polishing additive comprising an amidine compound and/or a quaternary salt of an amidine compound (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2002-249762).